1. Field of the Invention
The present invention relates to a deflection yoke, and in particular, to a deflection yoke for preventing fluctuation of the deflection yoke by maintaining a firm engaged state while preventing fracture and damage thereof caused by an assembling shock generated when assembling the printed circuit board.
2. Description of the Prior Art
In general, a deflection yoke is employed for a TV set or a cathode ray tube (CRT) of a monitor to accurately deflect three-color beams scanned from an electron gun to a fluorescent screen coated on a screen of the CRT. The deflection yoke, which is the most significant factor of the magnetic devices of the CRT, plays a role of deflecting electron beams scanned from the electron gun so that the electric signals transmitted in time series can be reproduced as an image on the screen of the CRT.
To be specific, electron beams emitted from the electron gun travel straight forward the screen due to a high voltage, and illuminate a fluorescent body only at the center of the screen. Therefore, the deflection yoke plays a role of deflecting the electron beams so as to reach the screen in the order of being scanned from outside. This deflection yoke forms a magnetic field and uses a change of progressive direction by receiving power of the electron beams passing through the magnetic field so as to accurately deflect the electron beams to the coated fluorescent screen.
FIG. 1 is a side-elevational view of an ordinary CRT. As shown in FIG. 1, a deflection yoke 4 located at an RGB electron gun section 3 of a CRT 1 deflects electron beams scanned from an electron gun 3a to a fluorescent screen coated on a screen surface 2.
This deflection yoke 4 comprises a pair of coil separators 10 symmetrically coupled in upper and lower directions.
The coil separator 10 provided for insulating a horizontal deflection coil 15 and a vertical deflection coil 16 as well as for assembling the same at proper positions comprises a screen section 11a engaged with a screen surface of the CRT 1, a rear cover 11b, and a neck section 12 integrally elongated from the central surface of the rear cover 11b to be engaged with the electron gun section 3.
A horizontal deflection coil 15 and a vertical deflection coil 16 are provided on internal and outer peripheral surfaces of the coil separator 10 for forming a horizontal deflection magnetic field and a vertical deflection magnetic field with a power supply applied from outside.
A pair of ferrite cores 14 composed of a magnetic body are provided to surround the vertical deflection coil 16 for consolidating the vertical deflection magnetic field generated from the vertical deflection coil 16.
When a sawtooth pulse is applied to the horizontal deflection coil 15 and the vertical deflection coil 16, the deflection yoke 4 comprised as above determines a scanning position on the screen by deflecting the electron beams of red (R), green (G) and blue (B) emitted from the electron gun 3a of the CRT due to a magnetic field generated according to the Fleming""s left-hand rule.
Meanwhile, the deflection yoke as shown in FIG. 1 is roughly classified into a saddle-saddle type deflection yoke as shown in FIGS. 2 and 3, and a saddle-toroidal type deflection yoke as shown in FIGS. 4 and 5 in accordance with a winding structure of the coil.
In the saddle-saddle type deflection yoke shown in FIGS. 2 and 3, the horizontal deflection coil 15 of a saddle shape is installed on upper and lower sides of the internal periphery of the screen section of the coil separator 10 of a cone shape.
To reinforce the magnetic field of the vertical deflection coil 16, the ferrite cores 14 of a cylindrical shape are provided on an external surface of the screen section 11a of the coil separator 10.
A coma-free coil (not shown in the drawings) is installed around an external periphery of the neck section 12 of the coil separator 10 for correcting coma generated by the vertical deflection coil 16.
FIGS. 4 and 5 are views showing an ordinary deflection yoke of a saddle-toroidal type. A horizontal deflection coil is installed on upper and lower sides of the internal peripheral surface of the screen section 11a of the coil separator 10 of a cone shape, and the ferrite cores 14 of a cylindrical shape are provided on an outer peripheral surface of the screen section 11a. A vertical deflection coil 16 of a toroidal type is wound along the upper and lower sides of the ferrite cores 14.
A coma-free coil (not shown in the drawings) is additionally installed around the periphery of the neck section 12 of the coil separator 10 for correcting coma generated by the vertical deflection coil 16.
In the saddle-saddle type deflection yoke and the saddle-toroidal type deflection yoke, a printed circuit board is additionally installed on one side surface of the coil separator 10 for supplying power to the aforementioned horizontal deflection coil 15 and the vertical deflection coil 16.
FIGS. 6 and 7 are views illustrating assembled states of the printed circuit board in the conventional deflection yoke. As shown in FIGS. 6 and 7, a printed circuit board 100 is engaged with a side surface of the rear cover 11b of the coil separator 10 for electrically connect the deflection coils and diverse electric automotive equipments.
A plurality of penetrating holes 110 are formed at predetermined positions of the printed circuit board 100 with regular intervals. A pair of hook flaps 200 are protruded from the rear cover lib corresponding to the penetrating holes 110 for fixing the printed circuit board 100 without fluctuation.
Here, in the pair of hook flaps 200, protrusions 210 having a triangular flap shape, i.e., slopes extended from a front end to a rear end thereof, are formed at end portions thereof so as to be suspended on one side surface of the printed circuit board 100 upon penetration of the penetrating holes 110.
The pair of hook flaps 200 are distanced to be slightly farther than the distance between the pair of penetrating holes 110 so that one surface perpendicular to the protrusions 210, i.e., the suspending threshold can support one side surface of the printed circuit board 100 after being elastically inserted to the penetrating holes 110.
Supporting ribs 220 are elongated to the hook flaps 200 so that the protrusions 210 penetrating the penetrating holes 110 press one side surface of the printed circuit board 100 when in contact with the other side surface of the printed circuit board 100.
The supporting ribs 220 having a predetermined area in a board plank shape is provided to extensively support one side surface of the printed circuit board.
In other words, the protrusions 210 integrally formed with the hook flaps 200 and the supporting ribs 220 fix the printed circuit board 100 by being in contact with the respective sides of the printed circuit board 100.
In the conventional deflection yoke having the above construction, the printed circuit board 100 is fixed onto the coil separator 100, i.e., on the rear cover 11b, by being suspended by the hook flaps 200 integrally protruded from the rear cover 11b and by being supported by the supporting ribs 220 elongated to the hook flaps 200.
However, such a conventional deflection yoke poses the following problems as the assembling structure between the printed circuit board 100 and the rear cover 11b is made by the pair of hook flaps 200 and the penetrating holes 110.
To be specific, as shown in FIG. 7, a worker needs to forcibly insert the printed circuit board 100 to the hook flaps 200 in order to fix the printed circuit board 100 onto the rear cover 11b. In this process, the assembling force laid on the printed circuit board 100 by the worker causes a fracture of the printed circuit board 100 or a deformation of the hook flaps 200.
Moreover, the printed circuit board 100 and the rear cover 11b have a structure of being engaged by the pair of penetrating holes 110 and the hook flaps 200. Therefore, if a forming dispersion or an assembling dispersion is generated in the penetrating holes 110 and the hook flaps 200, the printed circuit board 100 is not stably fixed on the rear cover 11b but is fluctuated.
The above problems not only increase defective proportion of the products but also notably deteriorate the quality of products due to failure of firmly fixing the printed circuit board 100 onto the rear cover 11b. 
It is, therefore, an object of the present invention to provide a deflection yoke which can maintain a firm engaged state while reducing fracture and damage of the parts caused by an assembling force laid by a worker when fixing a printed circuit board onto a rear cover.
To achieve the above object, there is provided a deflection yoke, comprising: a coil separator including a screen section engaged with a screen surface of a CRT, a rear cover, and a neck section elongated from a central surface of the rear cover to be engaged with an electron gun section of the CRT; horizontal and vertical deflection coils provided on internal and outer peripheral surfaces of the coil separator for forming horizontal and vertical deflection magnetic fields; a printed circuit board engaged with the rear cover of the coil separator and having a plurality of slide grooves connected to a frame on an upper portion thereof and a plurality of penetrating holes formed beneath the slide grooves at regular intervals for electrically connecting each of electronic parts; upper hook flaps protruded from a side surface of the rear cover to have supporting ribs contacted with one surface of the printed circuit board at one end thereof and protrusions contacted with the other surface of the printed circuit board upon penetration of the slide grooves at the other end thereof; a lower hook flap provided on one side of the upper hook flap to have supporting ribs and protrusions for supporting both side surfaces of the printed circuit board by penetrating the same; and a guiding slope surface formed on the sides of the supporting ribs or protrusions to have a predetermined angle so that the printed circuit board can enter the space between the supporting ribs and the protrusions of the upper hook flaps with a predetermined angle.
The guiding slope surface according to the present invention is characterized by being formed on a side of the protrusions facing the supporting ribs of the upper hook flaps.
The guiding slope surface according to the present invention is further characterized by being formed on a side of the supporting ribs facing the protrusions of the upper hook flaps.
The guiding slope surface according to the present invention is also characterized by being formed within an angle range of 5-60xc2x0.